Conventionally, in a processing apparatus having an accommodation chamber for accommodating a substrate, when a processing gas or a purge gas is introduced into the chamber, it is known that particles attached to an inner wall of the chamber or surfaces of electrodes in the chamber are dispersed by a gas viscous force generated in a gas flow. If the dispersed particles are attached to the substrate, they give rise to such problems that they act as a mask during an etching processing of the substrate to form an etching residue, and as nuclei to deteriorate a film quality during a film forming process. Since an introduction of the processing gas or the purge gas into the chamber is indispensable during a substrate processing, a countermeasure for preventing particles from being dispersed when the gas is introduced into the chamber is required to solve the aforementioned problems.
For example, in Patent Document 1, in an apparatus including: a plasma generation chamber formed as a cylindrical resonator; a first magnetizing coil concentrically surrounding the plasma generation chamber; a second magnetizing coil coaxially disposed with the first magnetizing coil at a farther position than the first magnetizing coil from a wafer adsorption surface of a sample table; a vacuum exhaust device having a turbo-molecular pump and a dry pump connected to an outlet side of the turbo-molecular pump; and the like, there is provided a method including the steps of: forming a mirror magnetic field by the first magnetizing coil and the second magnetizing coil; cleaning an inside of the apparatus by using a gas in a high pressure region, wherein a gas pressure in the mirror magnetic field and the apparatus is 1.3×10−2˜1.3×10−1 kPa (0.1˜1.0 Torr); and further, cleaning the inside of the apparatus by using a gas in a low pressure region, wherein a gas pressure in the mirror magnetic field and the apparatus is 6.7×10−3˜1.3×10−1 kPa (5.0×10−2˜1.0 Torr).
Further, in Patent Document 2, in a dry etching apparatus including: a circular upper electrode and a circular lower electrode in a chamber disposed to be parallel to the chamber; and a gas inlet line for introducing a processing gas or the like in the chamber, there is provided a method for removing carbon based deposits attached to an inside of the chamber by active species of oxygen, including the steps of: fully exhausting the chamber to a vacuum; introducing an oxygen gas for cleaning into the chamber through the gas inlet line controlling a supply and a discharge of the gas to adjust a pressure in the chamber; and applying a predetermined powers to the upper electrode and the lower electrode to convert the oxygen gas into a plasma.
Patent Document 1: Japanese Patent Laid-open Application No. H4-186833
Patent Document 2: Japanese Patent Laid-open Application No. 2000-195830
However, when the carbon based deposits causing the generation of the particles are removed, in case the powers applied to the upper electrode and the lower electrode and the pressure in the chamber are not optimized, the carbon based deposits cannot be removed uniformly, and further, parts in the chamber can be damaged, resulting in a problem that the particles are generated in the chamber.